"Our job is to be tough!" O'Reilly exclaimed as the two talked over each other. "It's our job to vet you the best way we can. Look, you are too thin-skinned."

Trump fires near-daily broadsides against various media outlets that he feels cover him unfairly. Ahead of the Tuesday-night debate, Trump furiously tweeted not only at CNN, but also at Fox News, which he said was "not fair" in its coverage. Trump further attacked Fox host Megyn Kelly, whom he called "dopey," and various Fox pundits.

"You want to be president," O'Reilly said. "Tweet about Putin. Tweet about ISIS. I mean, it looks petty. It looks petty. Don't you think it looks petty? Don't you think it looks petty?"

Trump disagreed with O'Reilly and said he was simply calling out inaccuracies in the media.

Earlier in the interview, the Fox host also accused Trump of intentionally making over-the-top policy announcements and statements to provoke an emotional reaction from his supporters. Trump recently ignited a national firestorm by proposing a temporary ban on Muslims entering the US.

"Are you going to tell me tonight on this program that you don't say stuff just to get to the emotion of the voter? I know you do!" O'Reilly said. "You're telling me you don't do this to whip up the base and whip up your crowd?"

Trump again disagreed with O'Reilly and assured the host that he knew "more about policy than just about anybody."